I watch (and have watched) both.
I watch Kiara because she's cute, used to be hardcore needy of her audience, was a bit of a trainwreck mentally for a long while, and grew over the course of her 3 years in Hololive. It's a fun journy to see her grow and she fed into some of my saviourfag instincts and can work as good GFE because she just talks at you for hours about the most mundane stuff in her life and it's cute. In the last year-ish, she's slowed down a bit on the personal talk and seems to be leaning less and less on KFP as a support group for her, which is both a good and a bad thing depending on why you like her/her content.
FuwaMoco on the other hand is just joy. They stick to their character hard and do well playing off of each other to make a fun dynamic for streams. It's hard to say what they'll be like in a month or two given their PLs stream time was nowhere near what they'll be doing for Hololive so we'll see if they'll be able to handle staying in character as much as they will need to. It's also kinda surreal to be cheering someone on and watch them disappear, only for them to reappear on a much bigger stage, giving them the oppertunity to reach some of their personal goals.
In that regard, while I hadn't been following Kiara prior to HL, she opened my eyes to what makes the idol journy so much fun to watch and getting another person (or persons in this case) who have the same ambition and goals is a lot of fun. I'm excited to see them collab 1 on 2 in the future and think they will have a lot of stuff to talk about.
